Vitamins rubbished - again
waste of time, and that the so-called evidence to show their
apparent benefits either ignores the potential risks or focuses
only on certain results - a claim which has already sparked a
number of heated counter arguments.
The debate continues to rage over the efficacy of vitamins following the publication earlier this month of a report claiming that synthetic statin drugs were more effective than certain vitamins at reducing the risk of heart disease or cancer.
Advocates of vitamins have been fierce in their condemnation of the study by Professor Rory Collins and his team at the University of Oxford, pointing out numerous anomalies in the way the study was structured and reported.
But now another senior figure from the British medical establishment has added his voice to the debate, coming out in support of the Collins report.
Writing in the latest issue of the British Medical Journal, David Bender, senior lecturer in biochemistry at the Department of Biochemistry and Molecular Biology, University College London, said that apart from folic acid for pregnant women and vitamin D for the elderly, taking vitamins was largely a waste of time because the quantities involved were simply not large enough to do any good.
Bender said that the current methods of assessing whether vitamin intake had any significant beneficial effects had as yet been unable to provide any conclusive answer, and there is still no consensus on optimum intake levels or on whether taking nutrients is the most effective way to treat or prevent a range of illnesses.
He cited the example of beta-carotene, which has been shown to reduce the incidence of lung, prostate, and other cancers. He said that carotenes are antioxidants which reduce the damage from free radicals, themselves one of the risk factors for cancer or heart disease.
"However, most compounds that act as antioxidants do so by forming stable radicals that persist long enough to undergo metabolism to non-radical compounds. By definition they therefore form radicals that can penetrate deeper into tissues and plasma lipoproteins, and potentially cause more damage than the oxygen radicals they have replaced," Bender wrote in the Journal.
Bender did concede that vitamin D supplements could be beneficial for the elderly, as they helped strengthen the bones, and that folic acid taken periconceptually (i.e. in the period immediately before and after conception) had been clearly shown to reduce the risk of neural tube defects, but that other supposed benefits, such as fighting cancer or heart disease, were yet to be proven.
"The answer to the question of whether we should take a multivitamin tablet every day must be that unless our intake is inadequate as a result of a poor diet then supplements will probably do us no good - apart from folic acid taken periconceptually and, possibly, vitamin D by elderly people," Bender concluded.
Not surprisingly, Bender's editorial prompted a number of replies, many of which are posted on the BMJ website. The general tone of most of the responses is hostile, with many of the letters citing studies contradicting the claims made by Bender.
The proponents of nutrients as disease fighters are many and vociferous, but there is also an increasingly vocal lobby which urges caution. Will science ever be able to give us an exact answer, and in any case, does this really matter to the patients who can see for themselves that nutrients are of benefit to them?
